1. Field of the Invention
This invention relates to can crushing devices and more particularly to an improved can crushing apparatus which is electrically operated and capable of inexpensively crushing commercial beverage cans or the like of various sizes in a neat small form and in a quick, efficient and uniform manner.
2. Description of the Prior Art
Beverage cans such as aluminum and steel soda cans have been a continuing problem in today's ecology minded society. The wide number of beverages utilizing such form of cans creates the problem in which the cans after use must often times be separated so that they can be brought to a recycling center. Prior to bring it to the center, the volume or space consumed by such cans is substantial. Therefore, it is highly desirous to store such cans in a crushed or reduced compacted state so as to minimize volume storage requirements. It is also desirable to crush cans in such a manner that the crushed cans do not have exposed sharp edges.
Since many cans in the process of being disposed of contain a small residuum of liquid, vertically crushing them appears to be more desirable than crushing cans whose longitudinal axes are disposed in a horizontal dimention. However, when attempting to crush vertically disposed cans, the amount of force required to crush the can is extremely great, due to the inherent structure of the can to be crushed. The can itself in the topmost and lowermost regions are reinforced in strength by the forming of the can or the placement of the can lid. The weakest part of the can is usually the side of the can which is amenable to lower level inwardly directed pressures, directed inwardly towards the vertical axis of the can. Somewhat more force is required to deform either the uppermost or lowermost lateral surfaces of the can, but considerably less force is required than the amount of force required to compress a can which is not so deformed.
In a patent to Belfils, U.S. Pat. No. 4,133,261, a device is disclosed which requires considerable force to crush a can. In Belfils, the crusher has a base on which the can to be crushed is placed and means for crimping one side of the can when pressure is applied to the top of the can is provided. The crimping is accomplished by a bead on the bottom base. Since the crimping means is provided by a bead, cans of varying sizes require different crushing pressures. Since the cans are not restrained in Belfils, they can buckle into a wide variety of shapes and may be forcibly ejected during crushing, resulting in the injuries to the user.
In a patent to Dodd, U.S. Pat. No. 4,570,536, issued Feb. 18, 1986, an electrically actuated can crusher is disclosed, which simply applies a constant uniform force to the uppermost region of the can, whilst the bottommost region of the can is resting on a lowermost crush plate. Here, the crushing force required to crush a can is substantial and would require a motor of great size to crush cans of various strengths and thicknesses.
U.S. Pat. No. 4,358,994 to Talley, issued Nov. 16, 1982, teaches the application of a force to a can, directed inwardly on one side of the can, causing the can to bend almost in half, followed by an operation to flatten or compress the balance of the can into a relatively thin laminate. However, the Talley teaching describes a two step operation, in order to accomplish the preweakening of the can.
U.S. Pat. No. 3,889,587 to Wharton, issued June 17, 1975 discloses an apparatus which slits at least one side of the can, prior to a compression step. Here, the can is contained within a housing which prohibits the can from extending outwardly forcing the cut edges of the can to collapse inwardly.
U.S. Pat. No. 4,301,722 issued to Balbo et al on Nov. 24, 1981, teaches an apparatus having an opening through which the can is inserted prior to the crushing operation. Such opening deforms the sides of the can, as it is manually placed within the housing, followed by a crushing step wherein the moveable crushing plate is directed manually towards the stationary crushing plate.
U.S. Pat. No. 4,333,396 to Longnecker issued June 8, 1982 describes a two stage can crushing device in which a linkage is adapted to partially deform of the can, followed by a step in which the can is moved to a second can crushing head which completes the crushing operation. The protrusion, mounted in an offset manner to the center of the first movable crushing plate, applies a force to the can so as to deform the uppermost surface in an asymmetrical fashion permitting the can to be more easily crushed during the second stage of crushing operation.
U.S. Pat. No. 4,290,354, to Stevens, issued Sept. 22, 1981, teaches a manually operated beverage can crusher having affixed to the lowermost stationary crusher plate a pivotable plate upon which the can, prior to crushing, is rested. At the conclusion of the crushing operation, the movable plate may be pivoted so as to eject the crushed can from the confines of the housing to which it is contained.
International Patent Publication No. WO 81/02802, published Oct. 1, 1981, under the Patent Cooperation Treaty to Andersson, et al. teaches a can crushing apparatus having an upper pressure plate forceably downward directed, and having an elongated protrusion extending below its lowermost lateral surface for uniform operation upon the uppermost lateral surface of the can to be crushed. In another embodiment, the same inventors teach the lowermost pressure plates having two upwardly extending protrusions upon which the base of the can to be crushed is placed, whilst the uppermost surface of the can to be crushed is uniformly deformed by the single projection extending downwardly from the uppermost pressure plate.
There is thus a need for a can crushing apparatus which crushes a can vertically with a minimal amount of required force so as to produce a compacted can without exposed sharp edges, symmetrical in appearance, requiring the use of modest forces to crush the can.